CHA structure molecular sieve as well as preparation method and application of tail gas denitration catalyst of the CHA structure molecular sieve

Abstract

The invention discloses a CHA structure molecular sieve and a preparation method and application of a tail gas denitration catalyst of the CHA structure molecular sieve, and belongs to the field of chemical synthesis technology and application thereof. An N,N,N-trialkyl-(norcamphane-2-yl)-quaternary ammonium onium compound is used as an organic template agent to synthesize the CHA structure molecular sieve, the molar ratio of silicon dioxide to aluminum oxide ranges from 6 to 80, the average grain diameter is smaller than or equal to 500 nm, the total specific surface area is larger than or equal to 400 m2 / g, the total pore volume is larger than or equal to 0.20 ml / g, the micropore volume is larger than or equal to 0.10 ml / g, and the grain diameter size in the crystal face (-210) directionis 50-160 nm. After the molecular sieve is subjected to hydro-thermal treatment at 600-850 DEG C, the tetra-coordinated aluminum accounts for more than or equal to 90% of the total aluminum amount, and the hexa-coordinated aluminum accounts for less than or equal to 10% of the total aluminum amount. The molecular sieve provided by the invention has high hydrothermal stability without large crystal grains, shows high nitrogen oxide reduction characteristics after being exposed at high temperature and high humidity, and especially shows high nitrogen oxide reduction characteristics in a temperature range of 200-550 DEG C.

Description

technical field [0001] The invention relates to a preparation method and application of a molecular sieve with a CHA structure and a tail gas denitration catalyst thereof, and belongs to the field of chemical synthesis technology and its application. Background technique [0002] The silica-alumina zeolite molecular sieve is a CHA-type topological structure with a three-dimensional pore structure and orthogonal symmetry. The one-dimensional main channel is composed of double eight-membered rings, the pore size is 0.38nm×0.38nm, and the skeleton density is 14.5. The topological structure of CHA molecular sieve is composed of double 6 rings (d6r) connected by 4-membered rings to form a large cha cage. The d6r crystal plane faces the cha large cage. Cu ions can be stabilized in d6r at high temperature, allowing Cu ions to migrate. It is also the unique physical and chemical characteristics of small-pore molecular sieves with SCR reaction potential. In the literature (J.Phys.Ch...

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Problems solved by technology

[0006] The technical problem to be solved by the present invention is to overcome the SCR catalyst using synthetic molecular sieves loaded with iron and copper in the prior art to be active at low temperatures through the hydrothermal durability test. Lower defects, providing a copper-based SCR catalyst with high activity at low temperature after hydrothermal durability test and its preparation method

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